The invention relates generally to concrete form work and more particularly to improvements in apparatus that can be effectively automated to cast the inside surfaces of a corner as may be required in forming a tubular concrete structure such as an elevator shaft, box culvert, etc.
The prior art contains many different proposals for concrete form work and its assembly, manually or with some degree of automation, into functional units for concrete construction. Accordingly, various structures have been suggested to facilitate the positioning of concrete form panels as required in the casting of an inside corner forming a part of a concrete wall structure. The forming of such inside corners is concrete casting necessarily arises in the construction of concrete shafts for elevators and stairwells as well as in other concrete structures such as box culverts.
In the casting of inside corners for structures as mentioned above, it is an important objective that the surface be smooth and free from joint lines once the form panels and associated components are stripped from the hardened cast concrete. Still, it is important that the apparatus utilized to cast the concrete inside corner be as simple in construction as possible involving a minimum number of structural elements, certainly avoiding the necessity for use of a variety of detached or detachable elements which would be subject to becoming separated or lost from the overall apparatus thereby preventing reuse of the apparatus at a multiplicity of different site locations.
In large measure, the prior art has been unable to achieve the desired attributes of providing a unitized apparatus which can be automatically operated effectively in the casting of inside surfaces of a concrete corner, both in setting up the form panels and related components preliminarily to concrete pouring and in stripping the panels and components from the subsequently hardened concrete.
Accordingly, one of the principal objects of this invention is the provision of a form unit to cast the inside surfaces of a corner of a tubular concrete structure which will yield smooth inner surfaces at and adjacent the inside corner with the unit being subject to automatic set up and stripping of the form panels and components against which the concrete is poured.
Another essential object of the invention is the provision of a unitized concrete form unit for inside corner casting which is self contained such that manipulation of the elements making up the form unit may be carried out automatically, basically without independent support for any of the components making up the inside corner form unit.
A further object of the instant invention is to provide an inside corner form unit which is totally automated and easily subject to being operated hydraulically, solely in response to flow control of a pressurized hydraulic fluid.
An additional object of this invention is to provide an inside corner forming unit wherein automated operation enables the unit to be set up for initial concrete pouring followed by first stripping form panels disposed adjacent the inside corner which has been cast followed by stripping a corner member from the cast inside corner while the previously stripped form panels are held against relative movement to each other.